1. Field of the Invention
This invention relates to closure devices and, specifically, to closures which can be quickly opened and closed and which can provide access to the interior of a pressure or a vacuum vessel, a pipeline or conduit, or other types of equipment in which there is likely to be a pressure differential across a closed opening.
2. Description of the Prior Art
A variety of pressure and vacuum vessels are known in the prior art which require a closure device for access. For example, such equipment includes gas filters/filter separators, gas scrubbers, scraper and pig traps, meter provers, manways to pressure vessels, liquid phase separators/coalescers, and launcher and receiver barrels for pipe line use, and the like. Equipment of the above type often features an ASME and API quick opening closure for access to the vessel or equipment interior.
Perry Equipment Corporation of Mineral Wells, Tex., has, for many years, offered equipment of the above types including quick opening closures therefor.
U.K. Patent No. GB2172956, assigned to an affiliate of the present assignee, shows a closure for an equipment sub which includes a cylindrical aperture which is closed by a circular member having an O-ring seal. A locking arrangement on the circular member secures it within the aperture. The locking arrangement includes a plurality of arcuate segments which are linked together to form a substantially complete ring and are mounted on an annular flange of the circular member. The segments are pivoted outwardly to cause them to engage a step provided in the cylindrical aperture by a control arrangement.
While the above device provided a safe and workable closure for a pressure vessel, it was complicated in design and featured a sealing surface geometry which was less than optimum.
Thus, despite advances made in closures of the above described type, there continues to be a need for further improvement.
The present invention has as one object to provide a closure for an equipment sub which can be quickly opened and closed to provide access to the interior of a pressure or vacuum vessel or other type of equipment where a pressure differential exists across the closed opening.
The invention also has as its object to provide such a closure which is simple in design and economical to manufacture and which utilizes the minimum number of moving parts.
Another object of the invention is to provide a closure with an improved sealing surface which is less critical in tolerance than the prior designs and which will accommodate a standard O-ring seal instead of requiring custom seal arrangements.
Another object of the invention is to provide a closure having a pressure warning device integral therewith which assures the release of any remaining pressure within the vessel prior to opening the closure.
Another object of the invention is to provide a closure with an improved hinge mechanism which allows precise alignment of the closure with respect to the opening provided in the associated equipment sub.
These objects are accomplished in a closure for an equipment sub having a generally cylindrical aperture leading to a bore and a bore stop. The closure includes a cylindrical body for engaging and disengaging the cylindrical aperture. The cylindrical body carries a peripheral seal on an outer peripheral flange thereof for sealing within the aperture when in the engaged position. A plurality of arcuate segments are mounted on the cylindrical body in a ring-like, spaced-apart pattern. A common actuating means connects the plurality of arcuate segments for simultaneously moving the arcuate segments radially outward to engage the stop in the bore of the sub and thereby prevent axial movement in at least one direction between the cylindrical body and the bore of the sub.
The stop in the bore of the equipment sub preferably comprises a shoulder formed as a part of a wedge shaped annular recess in a wall of the equipment sub. The shoulder is engaged by the arcuate segments when the cylindrical body is in the engaged position. The annular recess leads to a seal region of the equipment sub. The seal region comprises a sloping surface relative to a line drawn parallel to a central axis of the cylindrical aperture, the seal region being engaged by the peripheral seal of the cylindrical body when the body is in the engaged position within the aperture.
The common actuating means can comprise a plurality of cross bars which extend generally radially of the circular body, each cross bar being coupled at an outer extent thereof to a respective one of the segments and being coupled at an opposite inner extent thereof to a central hub assembly which can be rotated to cause radial movement of the cross bars to move the segments outwardly or inwardly.
Each arcuate segment has a pair of spaced guide rods attached thereto. Each guide rod is received within an opening provided in an associated guide block which in anchored to the circular body. The guide rods are, in turn, attached to a cross bar which is used to connect the guide rods to a selected cross bar. Each cross bar is pivotally attached to the central hub assembly. The central hub assembly has a lever arm for rotating the hub assembly, wherein movement of the hub assembly causes radial movement of the cross bars to move the segments outwardly or inwardly.
Additional objects, features and advantages will be apparent in the written description which follows.